Electrical converter



Dec. 31, 1940. w. w. HANSEN HAL 2,227,376

'ELECTR I CAL CONVERTER Filed May 20, 1938 2 Sheets-Sheet l INVENTORS fi'ussELL H. VAR/AN WILL/AM 1M HAM; N-

Patented Dec. 31, 1940 UNlTED STATES PATENT OFFICE ELECTRICAL CONVERTER poration of California Application May 20, 1938, Serial No. 208,984

3 Claims. (Cl. 250---36) This invention relates, generally, to apparatus for the conversion of unidirectional or low frequency currents to currents of high frequency, and the invention has reference, particularly, to a novel electrical converter operating at frequencies of 108 or more cycles per second.

The present invention is related to that disclosed in copending application Serial No. 92,787 of William W. Hansen, one of the inventors herein, filed July 27, 1936, Patent No. 2,190,712 granted Feb. 20, 1940 which application covered a novel type of high efficiency resonant circuit adapted to high frequency uses and which has come to be known by the name rhumbatron. The broad l5 principle of this type of resonant circuit is utilized in the present invention and in the following is referred to by that name.

In the prior art of electrical conversion there are several known types of electromagnetic oscil- 20 lators, to some of which reference is made herein as follows: Three-electrode, Magnetron, Barkhausen and Multipacter. All these oscillators are adaptable to use with various types of tuned circuits such, for example, as ordinary Q5 condensers and coils, or tuned transmission lines. All of them have in their construction some kind of electrodes for the passage of space currents through the oscillator circuits.

The principal object of the present invention $0 is to provide a novel converter embodying the broad principles of the type of apparatus disclosed in the above application and adapted to perform the functions of the above mentioned known oscillators but at considerably higher eflilih ciencies, especially when operating at the higher frequencies, the same converter being of a form adapting the same for convenient use.

Uther objects and advantages will become apparent from the specification, taken in connection all with the accompanying drawings wherein the invention is embodied in concrete form.

In the drawings,

Fig. 1 illustrates the embodiment of this invention in a three-electrode type of oscillator.

5 Figs. 2 and 3 are modifications of Fig. 1.

Fig. 4: shows the invention adapted for serving the functions of a Barkhausen oscillator.

Figs. 5 and 6 are details of Fig. 4.

Similar characters of reference are used in all so or the above figures to indicate corresponding parts.

Referring now to Fig. 1, there is disclosed a resonant circuit I embodying the broad principles of the type disclosed in the aforementioned ap- 55 plication and referred to as a rhumbatron. In

this embodiment, the resonant circuit I is shown as comprising a hollow metallic wheel-shaped member. In the center of the member I there are two fiat circular face portions 2 and 3 spaced a sufficient distance apart to accommodate a 5 cathode 4 and a pair of control grids 5 and E. Grids 5 and 6 are connected respectively to two capacitive members 1 and 8 that are connected, in turn, through grid leaks 9 and I0 and condensers 36 to the cathode. The grids 5 and 6 0 serve, in use, as the control grids of a push-pull oscillator and are excited by the capacitive members l and 8 which are placed in the electric field inside the member I for capacitively coupling grids 5 and 6 to the fields at the correct potentials in accordance with the principles disclosed in application Ser. No. 92,787.

Instead of using elements I and 8, connection can be made directly to the inside walls of member I with simple conductors II and I2, by-pass condensers l3 and I4, and grid leaks 9 and III, as indicated in Fig. 2. Another alternative arrangement is to use coupling loops I5 and I6 as indicated in Fig. 3, in which case the grid leaks 9 and II] and the condensers I3 and I4 are connected to the cathode.

The cathode 4 is connected to the negative of a battery H. The member I is made air-tight and evacuated, although of course, if desired, the same need not be air-tight but can be enclosed in a container which is evacuated and air-tight, as shown in Fig. 2. Energy is taken from the oscillator as by a coupling loop I8, as shown in Fig. 1. The fiat portions 2 and 3 may be either closed as in Figs. 1 and 3, or perforated as in Fig. 2, without distinction as to their electrical operation. In either case they provide the boundary of the field between them and act as electron removing or collecting surfaces, as the case may be. Whether the electrons are collected by these flat portions or removed from the field by passing through the same is immaterial in theory.

The operation of the system insofar as the cathode 4, grids 5 and 6, and faces 2 and 3 are concerned, conforms with the known principles of three-electrode tube operation. In the novel arrangement of this invention, the new type of resonant circuit rhumbatron I employs the opposed surfaces 2 and 3 to serve both as anode plates and as part of the resonant circuit. Methods of coupling by capacitive elements I and 8, conductors II and I2, or loops I5 and IE to the field in the member I are similar in effect to that disclosed in copending application Ser. No. 92,787. The arrangements shown in Figs. 1, 2 and 3 present many advantages over the arrangements known in the prior art, among which may be mentioned the following: the resonant circuit I may act as the evacuated container, the interior surfaces 2 and 3 of the member are presented as easily cooled electrodes to serve as anodes, and the circuit can be designed to oscillate efilciently and with a high ratio of reactance to resistance at high frequencies. The principal limitations as to the operation of the arrangement are those imposed by the limitations inherent in three-electrode tube operation, which, although mitigated in part by the improved arrangements, cannot be overcome entirely by them.

Fig. 4 shows a third form of oscillator wherein oscillations are due to the to-and-fro movement of electrons between the grid and filament of the member I in a manner somewhat similar to the action of the Barkhausen type oscillator. In Fig. 4, the member I with opposed internal face portions 2 and 3 is used as the container of the system, as in Fig. 1. A cathode 4 of filamentary type is spaced between anode wires 2| and negative potential grid wires 22. The plan arrangement of the filament, anode, and negative conductors is shown in Fig. 5.

In the operation of the oscillator shown in Fig. 4,- electrons emitted by the cathode 4 are accelerated by the surrounding field in which they oscillate at a frequency at or near that of the system until their velocity falls to a low value when they eventually impinge on the anode grid M and return to a battery 23. The oscillations of the electrons in the space surrounding the cathode 4 and anode 2I sustain the electromagnetic field of rhumatron I and are controlled in turn thereby. The electrons are accelerated toward the anode grid 2I by the field between the cathode 4 and anode grid 2I which is modified by the presence of negative grid wires 22. The lines of electric force are curved as shown in Fig. 6, and they aclecerate electrons from the filament in directions perpendicular to the plane containing the cathode and anode and also at angles fromthe plane. The electrons oscillate around the conductors of cathode 4 and the anode grid 2I and negative grid 22 in loops resembling much perturbed ellipses and eventually, after losing velocity, stop on anode grid 2i and return to battery 23. The components of electron motion perpendicular to the plane of cathode 4 and anode 2| sustain ocillation of the circuit.

Having disclosed methods and means for adapting the rhumbatron type of resonant circuit in the structure of oscillators in which single parts of the structure perform a plurality of functions ordinarily performed by separate parts, it will be obvious to those skilled in this art that the rhumatron can be applied to practically any oscillator with which conventional resonant circuits are associated. The substitution of the "rhumbatron circuit for the conventional form will usually extend the range of emcient operation to higher frequencies than with ordinary circuits and will in many instances result in more eflicient operation.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In apparatus of the kind described, a hollow internally resonant conducting member having an axis of symmetry and reentrant internal portions extending in the direction of said axis of symmetry, a thermionic cathode substantially symmetrically located between said internal reentrant portions, and a grid structure also located between said reentrant portions, and means including said cathode and grid structure for producing electromagnetic oscillations in said internally resonant conducting member at the frequency thereof.

2. An electrical converter consisting of a resonant circuit containing an electromagnetic field bounded by conducting surfaces forming said resonant circuit, a first grid, a thermionic emitting grid in the same plane as said first grid, both of said grids being inside said resonant circuit, means for making said first grid positive with respect to said emitting grid, and electron control elements constituting portions of the conducting surfaces of said resonant circuit, the contained electromagnetic field coact i ng with said elements, said positive grid and said emitting grid at the frequency of said circuit for excitation thereof.

3. In apparatus of the kind described, an internally resonant hollow conducting body having an axis of symmetry and internally projecting portions extending in the direction of said axis of symmetry, a thermionic emitter of electrons in the form of a grid placed substantially symmetrically between said projecting portions, a second grid for collecting electrons coplanar with said emitting grid, means for making said second grid positive with respect to said emitter, a third grid coplanar with the said other two grids, and means for making said third grid negative with respect to said emitter, and so arranged that conductors of said third grid lie between each first grid conductor and conductors of said second grid, said three coplanar grids cooperating to produce electromagnetic oscillations in said hollow internally resonant conducting body at the resonant frequency thereof.

WILLIAM W. HANSEN. RUSSELL H. VARIAN. 

